Propane-insoluble pitch



United States Patent 3,288,701 PROPANE-INSOLUBLE PITCH Eugene M. Fauber, Hammond, Ind., and Harry J. Montag, Lansing, 111., assignors to Sinclair Research, Inc., Wilmington, Del., a corporation of Delaware No Drawing. Filed Oct. 22, 1963, Ser. No. 318,105 5 Claims. (Cl. 208-22) This invention is directed to a novel propane-insoluble pitch having propreties that make it particularly useful, for instance, as a roofing felt saturant and as a component in road paving compositions.

It is common knowledge that coal tar pitch and paving asphalts are not completely compatible, nor are roofing asphalts and coal tar pitch. A material compatible with both coal tar pitch and petroleum asphalt becomes a very desirable item, particularly in the roofing and roadpaving industries. Unfortunately, however, materials known to be compatible with both coal tar pitch and petroleum asphalt have heretofore'falled in one way or another to meet the required characteristics of a satisfactory roofing saturant or road-paving composition. For example, in road-paving the added component should have good adhesion tothe aggregate, good drying properties, low viscosity for a given boiling range, acceptable odor, and little, if any, irritation to human skin. Also when provided as an extender in paving composition, the resulting asphalt aggregate mix should have good stock-piling characteristics, that is, should remain workable for relatively long periods of time, generally at least two months without hardening when stored in piles, possess good hardening characteristics when used to patch damaged asphalt pavements, :and should be stable in service. When used as a saturant in the impregnation of felt for built-up roofs, the material should have good impregnation characteristics, low viscosity to facilitate handling, acceptable odor, and little, if any, irritation to human skin. 7

It has now been found that the propane-insoluble pitch of this invention possesses all of the aforementioned characteristics and is at the same time compatible with both coal tar pitches and petroleum asphalts. The combination of the aforementioned properties together with its compatibility with both coal tar pitch and petroleum asphalts makes the product especially valuable since it can be used successfully as a saturant in the roofing industry whether coal tar pitch or asphalt is preferred as a covering by the individual roofer and as an extender in the road-paving industry, particularly where coal tar pitch is used as a primer for the road followed by a final paving with asphalt.

The novel pitch of the present invention is obtained by the solvent extraction of petroleum bottoms derived from gasoline-producing catalytic cracking processes. The cracked oil is the residual oil produced as a result of the cracking of suitable mineral oil cracking feedstocks such as petroleum gas oils in the presence of catalysts such as silica-alumina or other catalysts, usually silica-based cracking catalysts, which are frequently in the fluidized state. In distillation of the cracked oil, generally at about 7 to 25 psi. pressure to a maximum or end point of about 650 to 750 F., to obtain gasoline and gas oils overhead, there is produced a heavy residue or distillation bottoms containing entrained catalyst. To

3,288,701 Patented Nov. 29, 1986 remove the catalyst, the residue is usually permitted to remain quiescent for a sufficient period of time to allow the catalyst particles to settle out, at which time the residue substantially free of catalyst may be decanted. In lieu of settling, the catalyst particles may be filtered or centrifuged from the oil, or such operations may be used in conjunction with settling.

In any case, there is obtained a clarified slurry oil, also referred to in the art as clarified oil. Clarified oil feeds suitable for production of the pitch of the present invention boil primarily in the range of about 400 to 1000 F. and have a 5 volume percent distillation point of at least about 500 F. or even about 600 F. and

volume percent distillation point of at least about 800 F. with at least F. units or even at least about 200 F. units, separating the 5 percent distillation point and the 95 percent distillation point. The clarified oil feed for solvent extraction can be the full range clarified oil, that is, the entire bottoms obtained as aforementioned by the distillation of the oil from the cracking unit or it can be suitable bottoms fractions of the. full range clarified oil, for example, a bottoms fraction having a 5 volume percent distillation point of below about 700 F. obtained, for instance, by vacuum distillation of the clarified oil, usually to about 50% or 'less bottoms. It is preferred that the cracking unit from which the clarified feed is obtained be operated at at least 50 percent conversion. Also, for reasonable yields of pitch from extraction, it is preferred that the clarified oil feed have an API of up to about 25.

The clarified oil feed is solvent extracted to provide the pitch of the invention as a raffinate or bottoms phase, an upper extract phase containing solvent and deasphalted oil also being produced. Separation of the upper phase provides the pitch of the invention, usually after any solvent in the raffinate is removed. Solvents suitable for use in the extraction are, for example, C to C paraffins, especially normal parafi'ins, with propane being preferred. Any solvent remaining in the pitch separated can be removed by simply heating at an elevated temperature generally about 300 F., for a few minutes.

The solvent to oil ratios and temperatures employed in the extraction will vary depending, for example, on the boiling range of the clarified oil feed, the solvent selected and the purpose for which the pitch product is intended, but in any event are selected to provide a pitch product having a specific gravity 77/77 F. of about 1.0500 to 1.1900; a minimum viscosity SUS at 210 F. of about 60 and a minimum needle penetration at 77 F., 100 grm./5 sec. (ASTM-D5) of about 20. Where the pitch of the invention is to be used as a roofing saturant, for example, it is preferred to have a needle penetration at 77 F. of about 50 to 80 and a softening point of about to F. whereas when the pitch is to be used as a paving material it preferably should have a viscosity at 210 F. of about 60 to 80 SUS. Generally, the solvent to oil volume ratios employed in the extraction will fall in the range of at least about 2, say about 3 to 8:1 and the temperature utilized for the extraction will often range from about F. to 200 F. Although a single extraction may provide the desired pitch, a number of extractions may be employed. Ordinarily the solvent extraction conditions are those which reduce the clarified oil to at least about 5% bottoms or raffinate, generally about 5 to 50% bottoms, based on the full range clarified oil. In cases where a select bottoms fraction of the full range clarified oil is solvent extracted, the percent bottoms, based on the to the remaining bottoms, until after six passes the desired pitch-like material was obtained. The pitch represented 9.4% of the full range clarified oil 'feed (column 1). The small amount of propane contained in the pitch was then select fraction may of counse be greater than 50%, gen- 5 removed by heating for a few minutes at 300 F. erally up to about 60% or more. In producing roofing The pitch obtained tested as shown in Table I, column saturant, for instance, the extraction is preferably cOn- 5. Two other pitches, shown in columns '6 and 7 of ducted in a manner that provides bottoms based on the Table I, were also obtained from the 50% bottoms clarifull range clarified oil of about 10 to 20%, while in the fi d 11 i a i il manner b t employing, i one case case of paving materials the bottoms are more often 10 (column 6), a propane/oil ratio of to 1, with 7 passes, obtamedm about 25 to 40% yield. 4 at 190 F. and one each at 180, 160 and 140 F., The Pltch of the ln'ventlon f be q as Such elthef and in the other case (column 7), a propane/oil ratio of as a roofing Saturant or p s matenal but alsqhas 7 to 1 with a single pass at 190 F. The pitch of column the added advantage of belngflble 'f 'f espaclally 6 represented 9.7% of the full range clarified oil and the in the making of paving materlals, dilutlon wlth untreated 15 pitch of column 7 35% f the f ll range larifi d 1L Clarified 011 Without losing mutual compatlblllty Wlth Tests on these pitches are also reported in Table 1, colasphalt and coal tar. For paving purposes, the pitch umns 6 and 7 of about 50430 Penetration at 9 can Each of the clarified oil pitches was tested for combe Cut back W P to about clal'lfied patibility with a coal tar pitch, an air blown asphalt and The followlng examples are Included to fPFther an asphalt obtained irom vacuum distillation of crude oil. trate the invention but are not to be considered llml The physical properties of the coal tar pit-ch, air blown asphalt and vacuum distillation asphalt are shown, respectively, in columns 13, 14, 9 and 10 in Table I. For com- EXAMPLE I parison the gas oil fed to the fluid unit catalytic cracker (column 2), clarified oil obtained there-from (column 1) A cla'rlfied O11 havmg the F Promrues w? In and residuals from vacuum distillation of the full range 1 Table I below fluldlzed clarified oils to 10% and bottoms (columns 3 and 4 Catalym 'f P Petroleum was dlstllled by respectively) were also similarly tested for compatibility steam vacuum distillation to a 50% bottoms fraction. with the asphalts and coal tar pitch Also included are The 50% bottoms fraotfon was thfin extrrfmted wlth 3O compatibility tests for the asphalts with each other and P Pf for 51X Passes solvent 011 P, with the coal tar pitch and residues obtained by similar 3/1 In a The made by propane extractions of a petroleum aromatic extract (col the clarified Oll bottoms fractions with propane in a mu 8) and reduced (columns 11 and closed batch treating kettle for 30 minutes at successive The compatibility test comprised di the P temperatures of 's ponents /50 by weight at 250 F. and permitting the and The miXluY Was permitted blends to stand in an oven at 1200 F. for 2 hours. The settle for three hours, on each pass, until two separate blends were then examined visually (at 200 F.) and phases were obtained. The deasphalted oil was drawn under the microscope (at 77 F.) for any indication of from the treater of each pass and additional propane added separation. The results are reported in Table I.

Table l Clarified on Gas 011 Charge From Fluid to Fluid Cata- Residue from Vacuum Distil- Residue from Propane Extraction of Catalytic lytic Cracking lation of Clarified Oil Clarified Oil Cracking Column No (1) (2) (3) Laboratory Tests:

Specific Gravity at 77 .9660 9042 1.1848 1.1712 1. 0862 Softening Point (R dz 13) F. 123. 5 111 Pentration at 77 F 22 53 Viscosity:

Saybolt Universal at 210 F. (SUS 45 45 1130 630 65 Saybolt Furol at 210 F- Color Compatibility of Blends 33th 50% Goal Tar Pitch (Col.

iiii 'nraa's'm E E3 E 5 $3;

1 l With 50% Asphalt (F101. 14): O iiifiifiinaa'sefi 5 3 E3 E 3 i '53 E 3 E 3 (3) With 50% Asphalt b61365 O Yiifiiirrressm E E 3 E 3 E 5 5 i3- i (3) With (33m, carbon star" (Col. 13)):

(336% Asphalt (Col. 10)) Visual Under Microscope Chemical Composition:

saturate 4. 5 Aromatics. 19. 2 Resins" 2.1 Asphaltenes. 74. 2 Distillation:

IBP, F 417 5%, F 557 F 91s Residue of Propane Extraction of Petroleum Extract Table l-Continued Asphalt from Vacuum Distillation of Crude Oil Coal Tar Pitch Asphalt Air Blown Roofing Residue from Propane Extraction of Reduced Crude Column No (8) (9) Laboratory Tests:

Specific Gravity at 77 F... Softening Point (R & B) F. Penetration at 77 F- Viscosity:

Saybolt Universal at 210 F (SUS) Visual Under Microscope... With (395% Coal Tar Pitch (Col. 13)).

(33%% Asphalt (Col. 10)):

Visual Under Microscope.

Chemical Composition:

Saturates Aromatics....- Resins Asphaltenes Distlillationz 1 Straw.

2 Two Phases, Sludge.

3 Complete.

4 Slight Oil Exudation on Surface.

EXAMPLE II T able ll Charge to Propane Treater.... AII Gravity of Clarified Oil. Solvent to Oil Ratio Volume Percent on Feed to Trcater. Number of Passes Temp. of Successive Passes Tests on Pitch:

Specific Gravity at 77 F Softening Point (R & B) F Penetration at 77 F Viscosity SUS at 210 F 1 Full range clarified oil. a a 2 4 at 190 1*., and 1 each at 180 F., 170 PI, 60 F., 140 F. 3 4 at 190 F.

The pitches obtained were tested for compatibility as in Example I with the coal tar pitch of column 13 in Table I above and the asphalts of columns 10 and 14 of the same table. The results of the compatibility tests are as follows.

Compatibility of Blends (1) (2) With coal tar pitch (col. 13) visual and under microscope Complete... Complete. With asphalt (col. 14) Visual and under microscope ..do Do. With asphalt (col. l0) visual and under microscope ..do Do.

The following example demonstrates the use of the pitch of the invention as a satisfactory saturant for roofing felt with either conventional roofing pitch or asphalt.

EXAMPLE III The pitch-like material of column 6, Table I was used to saturate a paper roofing felt. The weight of pitchlike material used as saturant was 160% based on dry paper. Weatherometer tests were run to compare the felt saturated with the pitch-like material with felts commercially saturated with coal tar and with asphalt saturants. Test specimens were prepared as follows. 2%" x 5" pieces of three felts were placed on galvanized steel plates with a high retaining rim around. the edges and were each covered with a 0.025" thick layer of roofing asphalt. Separate similar specimens were also prepared using roofing pitch. These six specimens were subjected to 30 Weatherometer cycles, consisting of 16 hours exposure to a carbon arc light at F. ambient temperature, 1 hour soaking time in water at 77 F. and 7 hours drying in air at 77 F.

The appearance of the samples after 30 weatherometer cycles, given below, showed that the felt saturated with the pitch-like material of this invention performed satisfactorily with either asphalt or pitch roofing, and as well as asphalt-saturated felt with asphalt roofing or tar-saturated felt with pitch roofin The results are summarized below:

Appearance of Specimens After 30 Weathcrometer Type of Sample Cycles Felt saturated with tar covered with pitch roofing.

Felt saturated with tar covered with asphalt roofing.

Felt saturated with asphalt covered with Surface glossy and smooth.

Surface dull and blistered.

Surface dull, cracked md this invention covered with asphalt roofing.

Composition of mix: Weight percent Sand'and limestone miX* 92.5

85-100 penetration paving asphalt 5.0

Pitch-like material of this invention (column 7,

Table I) *Sieve analysis of sand and limestone mix- S1eve size: Percent passing A 1 75 1/8II 5 No. 8 43 No, 14 32 No. 25 '20 N0. 52 14 No. 100 N0. 200 7 The above mix was prepared by thoroughly drying the aggregate (24 hours at 375 F.), then mixing the aggregate asphalt and pitch-like material at 300-325 F. for 1 minute.

The resulting mix when poured out in a pile was easily handled and could be scooped readily at 77 F. This mix when in a pile remained workable for three months, but when placed as a patch in a hole about 1 foot in diameter and 1" deep in a damaged asphalt pavement, provided a stable patch immediately after compacting. This patch hardened noticeably in one week. Difficulties with other stockpile mixes are that they harden in the stockpile, are not stable in service, or do not harden after patch application.

It is claimed:

1. A propane-insoluble pitch having a specific gravity, 77/77 F., of about 1.0500 to 1.1900, a minimum viscosity SUS at 210 F. of about 60, and a minimum needle penetration at 77 F., 100 gms./5 sec. of about 20, prepared by solvent extracting a petroleum bottoms feedstock produced from the catalytic cracking of petroleum gas oil, said feedstock boiling primarily in the range of about 400 to 1000 F. and having a 5 volume percent distillation point of at least about 500 F. and a volume percent distillation point of at least about 800 F. with at least about F. units separating the 5 volume percent distillation point and 95 volume percent distillation point, said solvent extracting being with a C to C paraffinic solvent at a solvent-to-oil ratio of at least about 2 to 1 and a temperature of about 130 to 200 F. to provide an extract phase and a raffinate phase and separating the phases to provide said pitch.

2. The pitch of claim 1 wherein the parafiinic solvent is propane and the solvent-to-oil ratio is about 3 to 8:1.

3. The pitch of claim 1 wherein the petroleum bottoms feedstock has a 5 volume percent distillation point of below about 700 F.

4. The propane-insoluble pitch of claim 1 having a viscosity of about 60 to 80 SUS at 210 F.

5. The propane-insoluble pitch of claim 1 having a needle penetration at 77 F. of about 50 to 80 and a softening point of about to F.

References Cited by the Examiner UNITED STATES PATENTS 1,989,045 1/1935 Merrill 20839 2,698,280 12/1954 Hersberger et al. 208-40 2,704,738 3/1955 Simpson 20839 2,858,231 10/1958 Watson 208--22 2,992,181 7/1961 Renner 20840 3,053,751 9/1962 Garwin 20845 3,087,887 4/ 1963 Corbett et al. 20845 DANIEL E. WYMAN, Primary Examiner.

P. E. KONOPKA, Assistant Examiner. 

1. A PROPANE-INSOLUBLE PITCH HAVING A SPECIFIC GRAVITY, 77/77*F., OF ABOUT 1.0500 TO 1.1900, A MINIMUM VISCOSITY SUS AT 210*F. OF ABOUT 60, AND A MINIMUM NEEDLE PENETRATION AT 77* F., 100 GMS./5 SEC. OF ABOUT 20, PREPARED BY SOLVENT EXTRACTING A PETROLEUM BOTTOMS FEEDSTOCK PRODUCED FROM THE CATALYTIC CRACKING OF PETROLEUM GAS OIL, SAID FEEDSTOCK BOILING PRIMARILY IN THE RANGE OF ABOUT 400 TO 1000* F. AND HAVING A 5 VOLUME PERCENT DISTILLATION POINT OF AT LEAST ABOUT 500* F. AND A 95 VOLUME PERCENT DISTILLATON POINT OF AT LEAST ABOUT 800* F. WITH AT LEAST ABOUT 100* F. UNITS SEPARATING THE 5 VOLUME PERCENT DISTILLATION POINT AND 95 VOLUME PERCENT DISTILLATION POINT, SAID SOLVENT EXTRACTING BEING WITH A C3 TO C5 PARAFINIC SOLVENT AT A SOLVENT-TO-OIL RATIO OF AT LEAST ABOUT 2 TO 1 AND A TEMPERATURE OF ABOUT 130 TO 200* F. TO PROVIDE AN EXTRACT PHASE AND A RAFFINATE PHASE AND SEPARATING THE PHASES TO PROVIDE SAID PITCH. 